The background of the present invention is the fact that the watch-making industry nowadays strives towards, and is capable of, integrating ever more complex functions into watches, and also in particular into mechanical watches, while at the same time trying to put this into practice in as technically simple—and aesthetically appealing—way as possible.
This has led on the one hand, for example, to the increasingly widespread use of timepiece modules which can be attached to the basic watch movement in a simple manner and, in cooperation with this, allow at least one additional function to be implemented, to the extent that this facilitates a modular construction. This is because such timepiece modules can be mounted on a basic watch movement without requiring any major changes in the latter, and, due to the cooperation with the basic watch movement, provide the watch with additional functions. For example, a timepiece module driven by the basic watch movement and mounted thereon can provide various astronomical data, an eternal calendar function, an acoustic repetition function, an alarm function, the display information required in regatta or diving watches, or similar information in a compact manner.
On the other hand, doing so necessarily moves the display information provided by the basic watch movement, which can consist, for example, of the standard date display, further away from the display plane defined by the watch dial, insofar as the timepiece module is typically placed between the dial and the basic watch movement. In the designs known to date, the result is that the user of the watch perceives the display information provided by the basic watch movement as being situated very much lower relative to the plane of the dial, and, in addition, that it is readable only within a reduced angular viewing range.
Similar difficulties also affect the use of other watch modules, not in direct cooperation with the movement, which can be attached to the movement and allow at least one additional feature to be implemented. In fact, such watch modules are becoming increasingly common as watches are more often equipped with complex functions and they can consist, for example, of a pressure gauge which is used to implement a depth gauge or altimeter, or the like. Such modules are able to function independently of the basic watch movement, and, like the above-mentioned additional timepiece modules, allow a modular construction. As in the case of a timepiece module, however, it is also possible when such an independent watch module is attached, depending on its placement relative to the movement, which is often radially around or below the latter, that the available display information provided, for example, on the top of said watch module, is situated in an unfavorable position relative to the plane of the dial. It then requires cumbersome and technically complex design changes to the basic watch movement to place the display information on the plane of the dial in order to allow the user a comfortable and aesthetically pleasing level of readability.
Finally, this set of problems is even found in some basic watch movements. For example, some timepiece movements comprise a display of the timepiece's power reserve, wherein this can be located, for example, on the dial side of the timepiece movement, depending on the configuration of the basic watch movement. To avoid overloading the dial of a complex watch with various displays, however, it can be desirable to display this information through a window at the bottom of the watch case. This would lead to a technically complex and expensive reconfiguration of the movement, however. Another example is a mode display that is sometimes present in basic watch movements, such as the on-off information of an alarm function in mechanical timepieces, which is usually located in the middle of the basic watch movement at the same level as the winding shaft, and which must be brought to the level of the dial, for example, by appropriate measures.
One approach to overcoming these difficulties, provided consideration is restricted to timepiece modules of the above-mentioned type, can be in designing and manufacturing timepiece modules to be as thin as possible, in order to keep the aesthetic disadvantage within limits as far as possible. However, this brings with it tight constraints in terms of technical feasibility, particularly in the case of certain functions to be installed in the timepiece module, as well as general cost increases in design and production. The same applies in connection with the other watch modules mentioned above, or with basic watch movements themselves.
In general, it is also known, in principle, in the watch-making industry to use so-called image guides which allow the optical displacement of an image from a given plane to a different display plane. Thus, for example, the U.S. Pat. No. 3,566,602 from as early as 1971 describes the use of image guides to deflect the display information from a display disk in the plane of the watch onto a display plane which is inclined in relation to the plane of the watch. A different application of image guides, or optical fibers in general, in watches, which is aimed more at implementing aesthetic effects, is disclosed in the patent application DE 2 936 953 from the year 1979. Further examples of the use of image guides in watches are given in the documents EP 0 181 809 or U.S. Pat. No. 3,966,303.
It should be noted, however, that following these publications, the use of image guides in the watch-making industry, in spite of their benefits specified in these documents, has not established itself and is extremely uncommon today, in fact almost non-existent to the best of the Applicant's knowledge. The reasons for this lie, inter alia, in the fact that the processing of image guides is relatively difficult due to their sensitivity, caused by their material properties, and that in particular image guides mounted in wristwatches, being portable objects, can be easily damaged by shocks. In particular, it should be noted that, due to their sensitivity to impacts and pressure, image guides can suffer damage very easily during their processing, for example, in the course of the production process of watches and in particular when being installed in a watch. This as well as the distance that is needed between the image guide and the original display plane of the display information can lead to at least partial loss of quality of the transmitted image, e.g., in the form of reduced edge sharpness and color intensity, and even to the extent of obscuring the image, thereby counteracting the potential benefits of image guides.